Sorry for pasting the somewhat lengthy lesson I found on another forum.
Just wanted to see if anyone agrees or disagrees with the part about engines that burn oil developing deposits from running synthetics.
True or poo?
"Synthetic oil, as its name implies, is synthetically prepared by sending the long chain (really long chain) hydrocarbons through an insane temperature in the presence of a catalyst "crack" them into smaller and more useful chains. In the "cat cracker" temperatures are so high that when the chains are reformed, they are in a super pure state. This pure state is precisely why you do not want it to burn. Like candle wax, it takes a very hot ignition and a very long time to combust. So then, when you run synthetic in a motor that will attempt to burn it, the oil won't fully combust and instead leave a sticky residue (almost exactly the same compound as tar) inside your cylinders. When your pistons move up and down a few thousand times per minute, that tar is pretty much like sand paper, scarring your rings and cylinder walls and adversly affecting your compression.
Regular oil is very impure, thus containing nitrogens and sulfur. Sulfur as we know combusts with very low ignition temperatures and combusts in a very exothermic reaction. I'm not saying it's okay to burn motor oil but it less painful on your motor than synthetic (specificaly on a higher milage motor). Hence why 2-stroke oil was invented. It is a quality lubricant but fully combusts with the ignition of gasoline which requires very little ignition temperature in vapor form (as we all know).
The thing about switching from conventional to synthetic later in a vehicals life is that after a certain amount of exposure to the conventional oil, the seals soak it up and various non-friction parts of the motor are kinda gummed up with it. When you introduce synthetic oil to the motor, the oil 'rinses' away most of those deposits, often loosening seals and causing them to leak."
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Just wanted to see if anyone agrees or disagrees with the part about engines that burn oil developing deposits from running synthetics.
True or poo?
"Synthetic oil, as its name implies, is synthetically prepared by sending the long chain (really long chain) hydrocarbons through an insane temperature in the presence of a catalyst "crack" them into smaller and more useful chains. In the "cat cracker" temperatures are so high that when the chains are reformed, they are in a super pure state. This pure state is precisely why you do not want it to burn. Like candle wax, it takes a very hot ignition and a very long time to combust. So then, when you run synthetic in a motor that will attempt to burn it, the oil won't fully combust and instead leave a sticky residue (almost exactly the same compound as tar) inside your cylinders. When your pistons move up and down a few thousand times per minute, that tar is pretty much like sand paper, scarring your rings and cylinder walls and adversly affecting your compression.
Regular oil is very impure, thus containing nitrogens and sulfur. Sulfur as we know combusts with very low ignition temperatures and combusts in a very exothermic reaction. I'm not saying it's okay to burn motor oil but it less painful on your motor than synthetic (specificaly on a higher milage motor). Hence why 2-stroke oil was invented. It is a quality lubricant but fully combusts with the ignition of gasoline which requires very little ignition temperature in vapor form (as we all know).
The thing about switching from conventional to synthetic later in a vehicals life is that after a certain amount of exposure to the conventional oil, the seals soak it up and various non-friction parts of the motor are kinda gummed up with it. When you introduce synthetic oil to the motor, the oil 'rinses' away most of those deposits, often loosening seals and causing them to leak."
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